The proposed work will study the modulation of ion channels in olfactory receptor neuron (ORN)s in response to odors. This work will be done using olfactory slices, a new tissue preparation. Various configurations of the patch-clamp technique will be employed to address the following specific aims: 1. Determine the properties of ORNs in the slice preparation. Using whole-cell and on-cell recording techniques the spontaneous activity will be observed and the voltage-dependent currents of ORNs examined. By filling the ORNs with Lucifier yellow the cell morphology will be correlated with the physiological measurements. 2. Evaluate to chemosensitivity of ORNs in the slice. Responses to odorants will be determined using the resistive whole-cell configuration and the conductances underlying the responses will be elucidated. Observe whether neighboring ORNs have similar chemosensitivity. 2. Describe the single channel properties of each channel that is modulated by a cocktail of odors. For each channel modulated by odors, determine if modulation by a second messenger can mimic the effect of the odor.